[Sovkiller]

Quote:

Originally posted by Voodoochile Al- I would certainly try it before I swap out your op-amps, no worries there. Depending on the bias of the buffer, you may even prefer the 627s now over the 637s, as the buffer does offer an (even) cleaner, more detailed high end as Sean pointed out. Not overkill, but the difference is there. Maybe you could discuss with your partner in ex-Perreaux goodness about it also. Granted you guys have radically different taste in cans... yet similar taste in amps.

Mark, feel free to mod it the way it needs to, I'm not worry about that at all, I just want it working properly nothing else....
Actually my major concern is not in highs or lows, I'm pretty satisfied with the overall freq spectrum of the amp, and the presentation it offers now the way it is, I just would like that extra little bit in the details without messing the highs as AD8610 tend to do with the CD3K, and I know that certainly the buffers will help on that, and if possible that little extra improvement on the soundstage to settle it "even more" natural....is a subtle improvement, but gladly it worth to do it.....

 

[ppl]

Ok **** happens. Please remember this was a small oversight on the part of the supplier as Larry ordered 25 volt caps. These were assumed to be so and the problem was not even discovered until recently. There are no reported problems with the Green caps and some have seen 30 Days. The reason for 5 caps as opposed to three is to implement the cross coupling bypass scheme as outlined in AN202 from Analog devices http://www.analog.com/UploadedFiles/...8865AN-202.pdf

Pg.3 Figure 3c depicting bypassing from the positive rail on one device to the negative rail on the other device. This is ideal for the PPA output stage, as it is indeed a virtual ground. Since this cross-coupled bypass cap from Left gain Positive to the Ground Channel Negative rail and vise versa between the Right channel and the remaining ground channel rail. This was something I have been trying to implement on the PPA board for over a year so I decided to just put it upon the Buffer since C2 is of no value on the PPA with Buffer board anyway. So this is why the additional two capacitors totaling 5. There are also more closely spaced holes so as to accommodate the Supper E configuration. This also is a new development yes the board gets improved on each order of boards as the more of something you make the better you can see a way to make it.
I am truly sorry that I failed to notice this oversight on the Green caps and I hope everyone can now go to sleep at night Knowing the Green Muse will perform just fine.

As for anyone thinking the OPA 637 are anymore tricky with the Diamond buffer than the HA-5002 is not using the latest five cap version this warning about the OPA-637 being unstable was with the three cap version. I personally observed no strange behavior from the 637 on the 5 Cap board. Infect I am presently Listening to Lary’s HD-650’s on my Almost ready for Primetime PPA with as DAC plus continuously adjustable Bass and Sporting a prototype of my Econ-O-Bias Buffer that is the same as the current Buffer however with Transistors more optimized for lower current operation. This is so far working on my wildest dream it is completely stable with the OPA637. This Econ-O-Bias version consumes only 10mA and outputs over 1 Amp of Current with 3500 Volts per u/Sec Slew rate and a 190 MHz. Bandwidth. Special low noise input transistors generally employed in Magnetic phono preamps. BTW this amp will also use separate batteries for the dac for further isolation of any digital signals contaminating my Amps supply lines. More over by reliving the primary batteries in the PPA from also having to power the DAC the load on the Primary batteries is reduced resulting in longer runtimes. I have observed 7to 8 hours of runtime with 800MAh NI-MH AAA with the DAC and amp powered at once. This is in stark contrast to the 5 Hours that a normal PPA DAC or PACE configured with the HA-5002 IC Buffers and you can easily see my obsession over such things.

 

[Voodoochile]

Thanks for weighing in on this, Phil. Regardless of these small bumps in the beginning of the road, the buffers are truly nice, and do represent an excellent upgrade. Thanks again for making it happen.

Quote:

Originally posted by ppl This Econ-O-Bias version consumes only 10mA and outputs over 1 Amp of Current with 3500 Volts per u/Sec Slew rate and a 190 MHz. Bandwidth.

That's impressive!

 

[ITZBITZ]

Larry, et. al, sorry if it sounded like I was pointing a finger. I had not even addressed the issue with Larry yet as my final PPA to use the diamond buffer is still on the drawing board. I'm still building/collecting parts so I was in no rush to find out more.

I probably got the third or fourth buffer off the line as I had it well before many others I know, so I don't doubt that the whole process is evolving to meet demand.

I've already been in contact with Larry, so I have no doubt that when I finally install this bad boy in my PPA it will sing to the bejezuz!

 

[guzzler]

my apologies as well, I sounded like a complaining little a*se there! LaRocco Audio have bent over backwards in all my correspondence with them to be helpful and polite. As I said to Larry in one of my first emails;

"I wish all companies were as good as LaRocco"

the Diamond buffer is a lovely piece of work, and I'm sure this is just a little teething problem, and they've been in touch to rectify the situation.

peace, g

 

[Sovkiller]

Quote:

Originally posted by xtreme4099 yeah darker and more detailed.

I think that all depends on the Z load, is not like a general rule, according to Phil he liked better the OPA627/637 with the CD3000 than the LT1122 with the diamond buffers, well at least he told me that once, I don't know if after the last tweaks that criteria had changed....as I was trying to tweak my PPA just for the CD3000, the cans I had, but maybe for other headphones the case will be different, and maybe some day I will try the LT1122, but honestly I'm pretty satisfied with the PPA the way it is now, and if the diamond buffers will improve that, I would like to see how......I'm really anxious waiting for it to come back...my only concern now to make the soundstage perfect, if the buffers get that, honestly I'm done here, until I hit the lotto to go for the "Big Brother" (R-10)

 

[Sean H]

Just wanted to extend my apologies to anyone who may have felt offended in some way with my "pics/pr0n" title to my thread. I see "pr0n" was edited out by a mod. Seems like a common term around here for pics, didn't think twice about it. Sorry about that everyone.

 

[ipodstudio]

Hey, Sean, I'm just getting Larry to fit a stepped attenuator to my PPA, BTW

 

[Sovkiller]

Quote:

Originally posted by Sean H Just wanted to extend my apologies to anyone who may have felt offended in some way with my "pics/****" title to my thread. I see "****" was edited out by a mod. Seems like a common term around here for pics, didn't think twice about it. Sorry about that everyone.

SeanH, as a geenral rule, porns here was always accepted as "pics of the interior" of any audio gear, I don't know why someone had to feel offended for that, if you do a search you will find thousands of posts with this word used with no other meaning that that....

 

[Sean H]

ipodstudio- Good move! Sounds like the way to go for sure. Lucky SOB!

Al- Yeah, I don't know, guess a mod didn't like it. I know there's a vigorous effort to cut down on profanity and such (although **** is not profanity). There's a particular member here who may have complained, but I respect him a lot and that's fine. Anyway...this is a public forum I guess, gotta respect that.

 

[ipodstudio]

...might just have removed it to "before" someone complained

preventative measure, so to speak. Can't imagine too many folks being bothered, though.

 

[kyrie]

I believe it's to prevent the forums being caught on a net search for "****." "pr0n" might be a suitable alternative.

 

[doobooloo]

That would be VERY interesting though, someone searching for p**n coming up with this page with amps and stuff...

Well, at least we all get very excited about this stuff...

 

[xtreme4099]

your forgetting the lab power ipodstudio ... another 300bux ...

 

[ipodstudio]

Quote:

Originally posted by xtreme4099 your forgetting the lab power ipodstudio ... another 300bux ...

I know, I'm going to get one later. Want to try the system first so I know what I gain when I get it